Supplement Article |
OP9. TRENDS IN USE OF TEMPORAL ARTERY BIOPSY FOR THE DIAGNOSIS OF GIANT CELL ARTERITIS (GCA): EXPERIENCE IN 2,539 PATIENTS AT 3 CENTERS OVER 11 YEARS
Mayo Clinic, Jacksonville, Florida, Rochester, Minnesota, and Scottsdale, Arizona, USA
Background: Temporal artery biopsy (TA-Bx) is the standard for the definitive diagnosis of GCA. We examined the use of TA-Bx for diagnosis of GCA over 11 years in 3 referral practices.
Methods: Pathology records from all patients undergoing TA-Bx for the diagnosis of GCA from 1994–2004 were examined. The relationship of positivity rate to biopsy length was examined, as was the practice of obtaining bilateral biopsies in patients whose biopsy on the first side was negative.
Results: 2,539 patients underwent TA-Bx. The median age was 74 years. 64% were female. Overall, length of biopsies decreased over time (P<0.001) at all sites and the proportion of patients undergoing bilateral biopsies fell over time (P<0.001) at the largest site. 681 patients (27%) had a positive biopsy. There was marginal evidence of a decrease in the proportion of patients with a positive biopsy at the largest site, but this could not be correlated with either fall in biopsy length or a fall in the rate of bilateral biopsies. 1,278 patients (50%) underwent bilateral TA-Bx. After a negative biopsy, the chance of finding a positive biopsy on the opposite side was 7.4%.
Conclusions: We could not demonstrate a relation between positivity rate and biopsy length and the minimal ideal biopsy length needed to identify GCA, when present, remains uncertain. Because pathologic evidence of the disease was present on only one side in 7.4% of patients undergoing bilateral biopsies, we recommend that bilateral biopsies be performed when the biopsy on the first side is negative.